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Biomedical subjects

C Smith

Publications and source records attributed to C Smith.

At least 919 records · Page 51Linked to original sources
PubMed1984

The effect of previous endocrine therapy on responses to a single dose of an LHRH analogue.

Serum concentrations of gonadotropins, testosterone and dehydrotestosterone were determined in patients receiving conventional endocrine therapy for advanced metastatic adenocarcinoma of prostate. The effect over 4 h of a single dose of a long acting analogue of LHRH was determined in these patients and compared to the response in patients receiving the analogues as first choice of treatment. Oestrogen therapy was found to suppress basal and stimulated gonadotropins and testicular androgens. Cyproterone therapy only partially reduced basal hormone concentrations and the response to the LHRH analogue was delayed. Orchidectomy resulted in elevated gonadotropins and an exaggerated response to the analogue. As patients who relapse while failing conventional therapy, may subsequently be treated by further endocrine manipulation, precise determination of their endocrine status should predict any expected benefit. Patients previously treated with stilboestrol are unlikely to respond to orchidectomy or LHRH analogue.

Adenocarcinoma↗
PubMed1984

Efficacy of polyglycolic acid (PGA) tubing stents in ureteroureterostomies.

Polyglycolic acid (PGA) tube stented, silastic stented and non-stented anastomoses were compared in 18 ureteroureterostomies performed in 13 dogs. Urinalysis, urine culture, BUN and serum creatinine and intravenous pyelograms were done periodically from 1 day to 6 months postoperatively and ureteral dynamics were performed at 6 months. Normal intravenous pyelograms were observed following 10 of 11 PGA stented, 3 of 4 silastic stented and 2 of 3 unstented anastomoses. PGA stents prevented extravasation and dissolved within 7 days without stone formation. Urodynamic and histopathologic studies revealed no significant differences among the 3 groups. The data suggest that PGA stents are as effective as silastic stents and do not require additional procedures for removal.

Animals↗
PubMed1984

A quantitative assay for the hydrolysis of structurally intact basement membranes.

A quantitative assay has been developed for the hydrolysis of native bovine anterior lens capsule basement membrane fragments. The rationale for using structurally intact membrane fragments as the substrate in enzyme assays is that the proteinase susceptibility of the various basement membrane components differs when examined individually compared to when they are present in their native state. The assay is based upon the solubilization of 3H-bound protein from a finely ground suspension of [3H]acetylated basement membranes. The acetylation reaction and the fragmentation procedure do not alter the morphology or proteinase susceptibility of the membranes. The initial rate of release of radiolabeled digestion fragments by six different proteinases is approximately linear over the first 15% of hydrolysis, and the initial rates obtained are proportional to the amount of enzyme over a wide range of enzyme concentrations. The labeling index of 3810 cpm/micrograms of basement membrane used in this study permits the solubilization of 50 ng of protein to be detected easily. Some information about the size of the protein fragments solubilized can be obtained by addition of trichloroacetic (5% w/v)-tannic acid (0.25% w/v) reagent to the supernatants from the assays, since this reagent appears to selectively precipitate larger fragments. An additional feature of this assay is that, since the substrate is radiolabeled, one can selectively visualize and analyze the size distribution of the digestion products by carrying out sodium dodecyl sulfate-gel electrophoresis with fluorographic detection. Based on the observation that these intact membranes are extensively digested by a number of common proteinases which have widely different substrate specificities, it appears that the hypothesis that a highly specific proteinase or class of proteinases is necessary for basement membrane catabolism is specious .

Acetylation↗
PubMed1984

Guidelines and an illustration of the use of ecological data for seeking clues of excess risk.

Ecological studies have acquired a bad reputation as weak scientific studies suffering from the ecological fallacy and many intractable limitations of data and method. In order to reduce these problems, it is suggested that analyses be focused on specific populations-at-risk, diseases, risk factors and places. In addition, seven guidelines are suggested which will limit the possibility of false positive results and provide the best clues for expensive, follow-up research. These guidelines are testing to make sure that the results are consistent across different times, places and methods. The guidelines were applied to finding the best clues for occupational-related cancers among white males aged 35-64 in the State of Illinois during 1950-1975. The most interesting clue found was that most coal mining areas in Illinois during the late 1960s and 1970s manifested the highest cancer mortality rates of trachea, bronchus, and lung and among the highest rates of increase of this type of cancer. This finding was unexpected because many studies have shown low lung cancer rates among coal miners.

Adult↗
PubMed1984

Simultaneous bladder and prostatomembranous urethral rupture from external trauma.

Simultaneous bladder and prostatomembranous (posterior) urethral ruptures from external trauma occur in 10 to 29 per cent of male patients with traumatic rupture of the posterior urethra. The records of 47 male patients with traumatic rupture of the posterior urethra were evaluated. A total of 8 patients (17 per cent) had simultaneous rupture of the bladder (4 extraperitoneal, 3 intraperitoneal and 1 both) and posterior urethra (5 complete and 3 partial ruptures). A fractured pelvis was present in all 8 patients, with an average of 3.1 associated injuries per patient. Both ruptures were diagnosed preoperatively in only 1 patient. In male patients with multiple injuries, including a fractured pelvis and rupture of the posterior urethra, a concomitant rupture of the bladder must be suspected and sought at surgical exploration.

Accidents, Traffic↗
PubMed1984

Idiopathic hypercalciuria associated with hyperreninemia and high urinary prostaglandin E.

A patient with idiopathic hypercalciuria and some features suggestive of Bartter syndrome is reported. Excessive urinary prostaglandin E (PGE) excretion and renal calcium leak were documented in this child. Treatment with aspirin and indomethacin reduced urinary PGE excretion and was associated with a decrease in daily calcium excretion. At the lowest levels of urinary PGE, the renal calcium leak was no longer evident although mild hypercalciuria persisted. These results suggest that PGE may play a role in some cases of idiopathic hypercalciuria.

Aspirin↗
PubMed1984

Ethylene-independent and ethylene-dependent biochemical changes in ripening tomatoes.

Fruits of Lycopersicon esculentum Mill cv Sonatine stored in 6% CO(2), 6% O(2), and 88% N(2) for 14 weeks at 12 degrees C, exhibited a temporal separation of certain biochemical events associated with ripening.The specific activity of two citric acid cycle enzymes, citrate synthase and malate dehydrogenase, fell substantially during the first 2 weeks of storage when changes in organic acid concentration also occurred. During this period, lycopene, polygalacturonase, and ethylene were undetectable.When fruit were removed from store, ethylene was evolved and polygalacturonase and invertase activity were rapidly initiated as was synthesis of lycopene.To determine whether the changes in organic acid metabolism were affected by ethylene, fruit was kept at 22 degrees C in either a normal atmosphere or a normal atmosphere supplemented with 27 microliters per liter of ethylene, and it was shown that in both atmospheres similar quantitative changes to those described above occurred in the citric acid cycle enzymes specific activities before any detectable increase in the specific activities of invertase and polygalacturonase. These latter changes, together with pigment changes, occurred between 2 and 3 days earlier in fruit exposed to ethylene, compared with those kept in a normal atmosphere.

Journal Article↗
PubMed1984

Semiautomated technique for identification of subgingival isolates.

A semiautomated approach for the characterization of subgingival bacterial isolates which economizes in media preparation, inoculation, reading, recording, and interpretation of results was tested. Test ingredients were added to a basal medium consisting of Mycoplasma broth supplemented with 5 micrograms of hemin, 0.5 mg of NaHCO3, and 0.5 mg of L-cysteine per ml. Sterile test media were aseptically dispensed into wells of sterile microtiter plates with a MIC 2000 dispenser. Inocula were grown in broth or scraped from agar plates, dispersed, and inoculated with a MIC 2000 inoculator. After 2 to 4 days of incubation, the optical density of growth was determined with an Artek 210 vertical beam reader at 580 nm and stored on a floppy disk. Reagents were added to each well, and the changes in optical density were determined. Thresholds for positive reactions were determined after extensive preliminary studies for each test. The tests were run in duplicate on each plate and interpreted with an Artek vertical beam reader. Tests that were run in this system included: fermentation of carbohydrates, decarboxylase reactions, reduction of nitrate and nitrite, ammonia production, hydrolysis of esculin, growth in the presence of inhibitory or stimulatory substances, and indole production. Approximately 80% of all isolates from subgingival samples could be characterized by this technique. Comparisons were made between the semiautomated and conventional identification techniques. Overall reproducibility of 2,980 strains by the semiautomated and conventional techniques were 95 and 90%, respectively. There was an 86% similarity of results by the semiautomated and conventional methods. The semiautomated technique was more rapid, less expensive, and as reproducible as the conventional method of identification.

Bacteria↗
PubMed1984

Prospective study of the human polyomaviruses BK and JC and cytomegalovirus in renal transplant recipients.

Forty eight renal transplant recipients were investigated prospectively for evidence of infection with the polyomaviruses BK and JC and cytomegalovirus. An active polyomavirus infection was shown in 31 patients (65%) and cytomegalovirus in 30 (62.5%). Half of the BK and JC virus infections occurred within the first three months after transplantation compared with 93% of the cytomegalovirus infections. Very late polyomavirus infections two or more years after the transplant were also shown. Cytology was useful in identifying polyomavirus but not cytomegalovirus infections, and 21 (68%) of the 31 polyomavirus infected patients excreted inclusion-bearing cells. Only three patients had symptoms possibly associated with the polyomavirus infection. One patient with BK virus infection developed ureteric stenosis and a second patient had malaise and vomiting. One patient with JC virus infection developed pericarditis and effusion. Renal function became impaired at the time of the polyomavius infection in eight patients (26%) and ureteric obstruction and pericarditis developed in two patients treated with methyl prednisolone for possible rejection. At the end of the study 25 of the 31 polyomavirus infected patients (81%) had functioning renal grafts. The detection of polyomavirus infection is important as increased immunosuppression needs to be avoided to prevent possible complications such as ureteric stenosis in transplant recipients.

Adolescent↗
PubMed1984

Gastric restrictive surgery for obesity: early radiologic evaluation.

This study was undertaken to determine the optimal radiologic examination techniques for the period immediately following gastric restrictive surgery to control obesity. Review of 450 examinations performed on 275 patients who underwent varied gastric restrictive procedures indicates that accurate evaluation requires prompt filming of the first swallow of contrast material in a specific initial patient position with only minimal fluoroscopic monitoring. It was found that the optimal patient position can be predicted, before contrast material is administered, by the orientation of the staples on an abdominal radiograph. Right posterior oblique (RPO) is the optimal starting position when vertical staple lines follow gastroplasty with a lesser curvature channel. Left posterior oblique (LPO) is optimal when horizontal staple lines follow gastroplasty. LPO is usually optimal when complex or confusing staple patterns follow gastric bypass operations and revisions of previous procedures to control obesity. However, RPO is the optimal orientation when the revision procedure is a vertical gastroplasty.

Humans↗
PubMed1984

The effects of bradykinin on the contractile activity of the isolated rat ovary.

Studies of ovarian contractility were carried out on 43 rat ovaries maintained in vitro. Eighteen ovaries showed spontaneous motility. In 65 of 155 tests (42%), synthetic bradykinin (3.75-25.0 ng/ml saline) produced sustained increases in ovarian tone, or stimulated phasic contractions. Failure to respond was related to the stage of the oestrous cycle. Sensitivity was highest around ovulation (00.00-04.00 h oestrus), when there were 25 responses in 26 tests, and the linear relationship between the response and the logarithm of the concentration suggested a threshold of 2.9 ng/ml saline. Sensitivity fell later in oestrus, and reached its lowest point in metoestrus (1 response in 20 tests). Since the plasma kinin system is activated before ovulation, and the threshold to bradykinin was within reported plasma kinin levels, it seems possible that plasma kinins are involved in contractile processes associated with ovulation.

Animals↗